This proposal requests funds for a JEOL JSM-7401F Field Emission Scanning Electron Microscope with embedded digital imaging, beam decelerating technology and high resolution backscattered electron imaging. The University of Iowa has one SEM (a Hitachi S-4000 acquired in 1989) to serve the entire campus. The current system cannot provide images of immunogold labeled samples at low accelerating voltages and a second system is critically needed because having only one system is severely limiting access by investigators. From February 1, 2004 to January 31, 2005, 87 investigators from 54 faculty labs in 22 departments and 6 colleges used the S-4000 SEM. 30 of the 54 faculty labs have NIH funded research grants totaling over $38,000,000.00 annually. To better support this research, it is critical to have ready access to state-of-the-art instrumentation. Heavy usage requires Investigators to reserve the Hitachi S-4000 SEM 2-3 weeks in advance. The system is made available 24 hrs a day to accommodate investigators. In addition, an average of 20 students a semester enroll in formal Microscopy Research classes. SEM short courses and workshops are also offered on a regular basis. Downtime for maintenance on the S-4000 has been nearly 25% and is due to the combination of very heavy use, difficulty in obtaining replacement parts and inexperienced service support. The new FESEM would be conveniently located in room 80 of the Eckstein Medical Research Building under the supervision of The University of Iowa Central Microscopy Research Facility (CMRF). Administration, maintenance as well as high-level technical assistance and training will be provided by experienced staff. Institutional commitment is strong, providing $39,000.00 in salary support for a Research Assistant and $14,000.00 towards the annual service contract on a continuing basis as well as $12,550.00 to upgrade a cryostage to be used on the JEOL JSM-7401 F. The five NIH funded faculty providing research descriptions are the heaviest users of the S-4000 SEM. Apicella will study human pathogenic bacteria. Welsh will investigate human airway epithelia cell biology in relation to Bardet- Biedl syndrome and other diseases. Grose is involved in determining the mechanism of human herpes virus infections. Wilson examines Leismania compromised human macrophages. Starner will study the relationship of Haemophilus biofilms to infection and inflammation in Cystic Fibrosis patients. [unreadable] [unreadable]